The first time I remember it happening was April 2, 2014. I was chaperoning Olivia’s 1st grade fieldtrip - a commitment I had made to her, her teacher and her classmates “BC” (Before Cancer), and the first time since “AD” (After Diagnosis) that I was shifting my physical presence from Callen to Olivia.

I took my place at the front of the bus – the novelty of bouncing around in the back having worn off some 35 years prior – and kept watch as eager faces filed past me. Their excitement at a day away from the mortar and brick classroom was both audible and palpable as it reverberated off of the hard surfaces and low ceiling of “the cheese”. The doors closed, the brake release squelched, and the bus lurched forward toward its destination, sending us all with a jolt into the barely-cushioned springs of our seatbacks.

It was at that moment that it hit me: What if this was both my first and last 1st grade fieldtrip as a mom?

I already had tremendous mommy guilt going into that day. All too often I had failed to plan ahead for Olivia’s school events. I had learned the hard way what happens when your daughter is the only one whose mother doesn’t show for a Mother’s Day Tea. I had experienced the pangs of guilt and regret when my (rather than the babysitter’s) appearance in the carpool lane elicited comments about the novelty of my presence. Shackled to the proverbial “golden briefcase” – or, in my case, speculum – it had somehow been deemed too difficult / unprofessional / costly to make last-minute changes to my schedule in order to attend school events that seemed to pop up with never quite enough notice.

I was such an idiot.

So despite it being a mere 20 days since diagnosis; despite having considerations and logistics now significantly greater than 40 inconvenienced patients to contend with; despite being nowhere near ready to leave Callen’s bedside, there I was. Whatever I had been afraid of in the past suddenly paled in comparison to what I feared now - that I might never experience this with Callen.

We think about our children’s futures from the moment we know we’re expecting them. We literally see it in their eyes (and other attributes) when, immediately after birth, we begin to conjure up visions of their someday selves: “He has your lips.” … “She looks just like my baby picture!” … “Oh, thank goodness he got your nose.”

But what happens when you suddenly go from wondering who and how and what they will be, to wondering if they will be at all?

The hard and honest truth is that I’ve thought about this more times than I’d care to admit these past 600-some-odd-days. And it’s not just me: for Jim, moments of solitude and sentiment alike can spiral into a trip down the proverbial rabbit hole. For me, an innocent question, an everyday experience, even a joyful occasion can precipitate an indescribable angst. It is this near-daily confrontation with that fear (whether for my own child or one of a fellow cancer family) that obviates the concept of ordinary, renders the mundane obsolete, and infuses most everything with more than a hint of bittersweet.

It’s asking Callen, who is engrossed in a video game, to come set the table – only to cringe when he responds, “I’ll be there after I die, Mom!”

It’s my heart soaring when Callen heaps repetitive spontaneous “I love you, Mom”s upon me, then sinking when I worry he’s paying them forward for some godforsaken day when he can’t.

It’s watching Jim dress a visibly frail Callen in a tiny tuxedo before taking the stage at a charity event, and gasping for air when my thoughts fast forward to readying him for prom.

It’s entering Callen’s upcoming birthday into my new smartphone and having to regroup when it asks whether I’d like to set that as a repeating event - and if so, for how many years into the future?

It’s Jim ceremoniously marking the occasion of Callen’s first day of school, vowing to recreate the day at the start of his senior year, and then breaking down as an unwelcomed uncertainty intrudes on the moment.

It’s biting my lip to dam the welling tears as I watch newlyweds take their first spin on the dance floor, only to have them overflow when Jim leans in and whispers, “We’ll get him there one day. I promise.”

It’s what happens when your presence has been requested at more children’s funerals than birthday parties of late.

It’s what prevents me from wishing away the long and often lonely days of treatment. Because at least we’re still here, we’re still together, and we’re still fighting – which Jim and I are both keenly aware would not be the case had this happened when we were Callen’s age.

It’s what kept us from marking the recently-passed halfway point in Callen’s treatment with little more than a nod to the mathematical balance. Because we don’t know what the end (or any day in between, for that matter) is going to look like, feel like, or give way to. So we’d best stay right here for - and in - the moment.

A few weeks ago, ironically while the world waxed nostalgic about Marty McFly’s 30-year-old forecast for the future, I climbed aboard another big yellow school bus. The destination this time was a nearby pumpkin patch, where we were going to learn about (of all things!) the life cycle. I took my place near the back of the bus – right over the rear wheel- and kept watch as the eager faces filed past me. And there in the midst – perhaps most excited of all - was Callen, who took a seat directly behind mine.

The bus doors closed, the brake release squelched, and the bus lurched forward toward its destination. And it was at that moment that it hit me: this was, for sure , my first – and last - first kindergarten fieldtrip as a mom. But before my mind could race ahead to assign any additional poignancy to the moment, Callen delivered a well-timed knee into my barely-cusioned seatback - jolting me perfectly, if not a bit painfully, back to the present.